Interference effect between $��$ and $��(1520)$ production channels in the $��p \rightarrow K^+K^-p$ reaction near threshold
説明
The $��$-$��(1520)$ interference effect in the $��p\to K^+K^-p$ reaction has been measured for the first time in the energy range from 1.673 to 2.173 GeV. The relative phases between $��$ and $��(1520)$ production amplitudes were obtained in the kinematic region where the two resonances overlap. The measurement results support strong constructive interference when $K^+K^-$ pairs are observed at forward angles, but destructive interference for proton emission at forward angles. Furthermore, the observed interference effect does not account for the $\sqrt{s}=2.1$ GeV bump structure in forward differential cross sections for $��$ photoproduction. This fact suggests possible exotic structures such as a hidden-strangeness pentaquark state, a new Pomeron exchange and rescattering processes via other hyperon states.